Autonomously dispensing media on relatively large surfaces may present unique challenges. The relatively large surfaces may be three-dimensional. Relatively large surfaces may include billboards, motion picture, television and/or live theater sets and backdrops, surfaces of transportation vehicles, e.g., aircraft, water craft, trains and/or automobiles, buildings and/or fabrics. Whether dispensing ink, paint, dye, a coating or some other medium, it may be difficult to accurately apply the medium manually over the relatively large surface. When dispensing multiple layers, e.g., to generate images that may include multiple colors, accurate spatial registration may be important. Covering most or all of the surface may necessitate moving about the surface and the entire surface may not always be visible. This may create difficulties in registration and in generating the desired image, in general.
In some cases, a dispensed medium, environment and/or surface may be “dull, dirty and/or dangerous.” In such cases, manually dispensing the medium may be undesirable. It may therefore be desirable to provide a method and system for dispensing a medium on relatively large three dimensional surfaces that includes automation, e.g., a programmable robot. The programmable robot may include an end-effector configured to dispense the medium, e.g., a print head configured to dispense ink.
It may be appreciated that programmable robots may be used in automated and/or semi-automated manufacturing systems. In some cases a programmable robot may be mounted on or may include an overhead gantry system. The overhead gantry system may necessarily be constructed with high accuracy to help provide acceptable accuracy for robotic manufacturing activities. In other words, the positioning accuracy of the programmable robot may depend on and/or be limited by the gantry system. It may be further appreciated that such a gantry system may be limited to a defined work space. In other words, the work space may be defined by the gantry system and its range of motion. Further, the gantry system itself may occupy a relatively large area thereby increasing the space required by the manufacturing system. It may also be appreciated that, once constructed, a gantry system may not be easily relocatable so that a manufacturing process may be limited to the location and range of motion of the gantry system, as constructed.
Accordingly, it may be desirable to provide a programmable robot whose positioning accuracy is relatively less reliant on the construction accuracy and/or tolerances of the gantry system. It may also be desirable, in some cases, to provide a programmable robot that is mounted on a mobile platform to avoid costs, space requirements and positioning limitations associated with a gantry system. A mobile platform may allow a programmable robot to operate in multiple locations
It may be appreciated that using a programmable robot to dispense a medium on a relatively large three dimensional surface may also present challenges. For example, it may be desirable, depending on the medium being dispensed, to dispense the medium over a relatively limited time period. In order to achieve this, it may be desirable to move the end-effector, and therefore the robot, relatively quickly. It may be appreciated relatively quick movement combined with positioning accuracy may be difficult to achieve. It may also be appreciated that a positioning system may be subject to measurement noise in detecting position accurately and process noise in moving the end-effector. The positioning system may depend on a model of the programmable robot. The model may include inaccuracies that may affect positioning accuracy. Process noise and/or model error may depend on physical parameters associated with the robot. Measurement noise may depend on accuracy and/or resolution of position sensors and/or processing devices coupled to those sensors. Such noise may contribute to inaccuracy in positioning and orientation. It may therefore be desirable to include an estimate of end-effector position and/or orientation to reduce or eliminate the noise and/or model inaccuracy effects and thereby improve accuracy.